Microstructure characterization of hydrothermally synthesized PANI/V₂O₅·nH₂O heterojunction photocatalyst for visible light induced photodegradation of organic pollutants and non-absorbing colorless molecules

Highlights: • Novel structure of PANI intercalated V₂O₅ hybrid nanocomposite (PV NC) has been synthesized. • Microstructure characterization is made by analyzing XRD pattern and FESEM/HRTEM images. • PV NCs exhibit significant enhancement in photocatalytic degradation of RhB compared to pure PANI. • PV NCs shows remarkable real visible light photocatalytic activity towards non absorbing test molecules. - Abstract: Polyaniline intercalated vanadium oxide xerogel (PV) hybrid nanocomposite (NC) with novel structure has been successfully synthesized through a simple hydrothermal route. Detailed structure and microstructure characterization of PV NC is illustrated through Rietveld refinement of XRD data and FESEM/HRTEM images. Both FTIR and XPS spectra confirm the presence of PANI and water molecules within the NC and partial reduction of V⁵⁺ to V⁴⁺, corroborating with the results of XRD pattern analysis. Core-shell structure of PV NC, where PANI sheath layer acts as a shell covering around V₂O₅·nH₂O crystalline core is confirmed from HRTEM images. Successive morphological changes of PV NC with different reaction time have been revealed from FESEM images. UV–vis spectra also confirm the formation of PV NC. Intercalation of water and PANI layers into V₂O₅·nH₂O layer leads to a structural phase transition from orthorhombic to monoclinic phase due to substantial increase in interplanar spacing of (00l) of orthorhombic V₂O₅. The photocatalytic property of the as synthesized PV NC has been reported for the first time, with a promising photocatalytic activity for the degradation of organic dye, Rhodamine B (RhB) under visible light irradiation. It is attributed to a synergic effect in between PANI and V₂O₅·nH₂O xerogel. The photocatalyst also shows remarkable real visible light photocatalytic activity with non-absorbing colorless test molecules like phenol and antibiotic kanamycin.